A040128 - OEIS

%I #8 Sep 08 2022 08:44:53

%S 2,7,11,13,31,43,47,67,103,107,113,137,157,163,167,173,179,181,199,

%T 211,223,229,269,271,311,331,347,349,367,379,383,397,401,439,443,461,

%U 479,491,499,503,509,547,569,571

%N Primes p such that x^4 = 14 has a solution mod p.

%H Vincenzo Librandi, <a href="/A040128/b040128.txt">Table of n, a(n) for n = 1..1000</a>

%t ok [p_]:=Reduce[Mod[x^4 - 14, p]== 0, x, Integers]=!= False; Select[Prime[Range[180]], ok] (* _Vincenzo Librandi_, Sep 12 2012 *)

%o (Magma) [p: p in PrimesUpTo(800) | exists(t){x : x in ResidueClassRing(p) | x^4 eq 14}]; // _Vincenzo Librandi_, Sep 12 2012

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_.